Try: btrfs-snapshots.sh --help
Setup daily btrfs snapshot of all mounted subvols in /etc/fstab:
/etc/fstab
sudo cp btrfs-snapshots.sh /etc/cron.daily/btrfs-snapshots
If you want hourly bakups, just enter:
sudo cp btrfs-snapshots.sh /etc/cron.hourly/btrfs-snapshots